Time-indicating apparatus



July 22 1924.

H. E. WARREN TIME INDICATING APPARATUS Filed April 15 1918 I5Sheets-Sheot 1 H. E. WARREN TIME INDICATING APPARATUS July 22. 1924.1,502,493

Filed April 15 1918 3 Sheets-Sheet 2 R al/1.4 TIMI IN VEN TOR.

July 22 1924.

H. E. WARREN TIME INDICA'IING APPARATUS Filed Aprn 15 1918 3 Sheets-Shut5 INVENTOR. W6. WW

ATTORNEY Patented July 22, 1924.

UNITED STATES PATENT OFFICE.

HENRY E. WARREN, OF ASHLAND, MASSACHUSETTS, ASSIGNOR TO WARREN CLOCI:COMPANY. OF ASHLAND, MASSACHUSETTS, A CORPORATION OF MAINE.

TIME-INDIGATING APPARATUS.

Application filed April 15, 1918. Serial No. 228,688.

To all whom it may concern.

Be it known that I, HENRY E. WARREN, a citizen of the United States,residing in Ashland, county of Middlesex, and State of Massachusetts,have invented an Improvement in Time-Indicatin Apparatus, of which thefollowing description, in connection with the accompanying drawings, isa specification, like characters on the drawings representing likeparts.

My invention relates to clocks or like apparatus, and in one of its asects rel..tes to clocks designed to compare tlme indications derivedfrom independent sources; as for instance the time indications given bythe standard clock Work with those had from a synchronous alternatingcurrent motor. The invention has for its general object an improvedarrangement 'ofparts affording an accurate, reliable and serviceableapparatus in which such indications may be readily compared and forcorrecting variations in time indications.

My invention has particular application where it is desired to regulateone of the sourcesof time indications so that two such independentsources may be made to give substantially the same time indications; forinstance where it is desired to regulate the frequency of thealternating current to synchronous motors giving time indications sothat their indications are made to agree with those of a standard timepiece in the manner disclosed in Letters Patent No. 1,283,431 issued inmy name on October 29, 1918.

To. give effect to my invention, I have found it expedient to have handswhich are impelled separately by the independent sources of time,traverse the same indicating dial. Such an arrangement facilitates theexact visual comparison of the indications, while a concentricarrangement. ermits the relative angular displacement o the hands beingmade an index of the error which may exist between the respective timeindications given by the two sources.

In further giving eifect to my invention, it is desirable that thesource which is made the standard of comparison should have veryaccurate time keeping qualities, and also have means for correcting withgreat precision any deviations in its time indications from standardObservatory time signals such as are regularly sent out from Washington.To this end I have arranged, in a novel manner, to kee the spring tenson in the source, or time lieeper serving as the standard of comparison,substantially constant, by having its spring or driving means re-woundconstantly by as much as it runs down; the rewinding may be convenientlyaccomplished by the synchronous motor which gives the other timeindications. Also to correct for the deviations in the standard timekeeper from the standard time signals I provide my standard time keeperwith a device for accelerating or decelerating at will the movement ofthe timing element or pendulum, in my time keeper.

Such device is preferably an electro-magnetic one and is made withadvantage, to function in two ways, one by applying a constantcorrection continuously to the movement of the timing element, the otherby applying a definite correction to such movement for a limited timeonly.

These and other features of this invention will be pointed out in theclaims at the end of this specification.

Fig. 1 is a front elevation of a time indicating apparatus embodying theinvention.

Fig. 2, a side elevation of the apparatus shown in Fig. 1.

I, Fig. 3, a diagram illustrating one'form of mechanism for regulatingor setting the apparatus shown in Figs. 1 and 2,

Fig. 4, a plan of a modified form of time indicating apparatus and Fig.5, a front elevation of the apparatus shown in Fig. 4.

Referring to Figs. 1, 2 and 3, 10 and 11 represent the pendulum bob androd of a clock movement having an escapement 12 and wheel 13, to whichpower is transmitted from the main spring 14 through gears andpinions15, 1e, 17, I8, 19, 20, 21, 22, in a manner well understood, andmotion from the escapement is transmitted by pinion 23 and ear 24 to asleeve 25, which carries a ban 26, which cooperates with a ial ahaving'numerals 1 to 5, which indicatethat the hand 26 makes a com leterevolution? once in five minutes. The hand 26 constitutes a revolvingmember or element indi cative of standard time.

27 represents a self-starting synchronous motor, which may be such as isshown and described in another application Se. No. 138,763 filed by meDec. 26, 1916. The motor 27 drives a shaft 29 through a slip coupling28, and motion is transmitted from the shaft 29 by pinioii 30, gears 31,32, and pinion 33 to shaft 34 upon which is fastened the hand 35. Theshaft 34 extends through the sleeve 25 and the hand 35 is thusconcentrically mounted with respect to the hand 26 and constitutes, atime element driven by the synchronous motor 27, and the ratio of thegears connecting the motor 27 with the hand 35 is-such that the latterrevolves at precisely the same rate as the hand 26-and coo erateswith'the dial a.-

nergy is also transmitted from the gear 31 through pinion 36, gear 37,pinion 38 and gear 39, pawl 41 and ratchet wheel 42 to shaft 40, towhich'the inner end of the clock s ring 14 is fastened, the outer end ofwhic spring is fastened to the gear 15.

'Iheratio ofthe gears from 31 to 39 is such, that normally the sprin 14will be wound b the motor 27 exact y as fast as the en ulum permits itto. be unwound. It will thus be seen that variation in the frequency ofthe alternating current which operates the synchronous motor 27,influences the rate at which the hand 35 is revolved over the dial a,and consequently variation in the frequency of the current is madelrnown to the operator at the power station in which the master clock islocated by noting the osition of the hand 35 with relation to the hand26.

Provision is made fonregulating. the rate of the pendulum with greatconvenience and precision, '"which is accomplished as herein shown byproviding the pendulum.

10 at its lower end with a permanent steel bar magnet 50, whichcooperates with and swings across flat coils of insulated wire 51 and52, so that the magnetic lines preceding from the magnet 50 areconstantly cutting the conductors in these coils. B

means of a battery of two or more cel s 53, I apply constant potentialacross the terminals of two potentiometers 54 and of known construction,and by means of sliding contacts 56 and 57, the position of which isindicated bymeans of scales 58 and 59, current= atplus or minuspotential istaken from the resistances 60 or 61. Contact 56 is connectedby the wire 62, contact maker 63 and 64, and conductor 65 at one end ofcoil 52, the other end of'whichis connected with the middle point of thebatteries 53, so that if contact maker 63 and 64 is closed by pushingdown on the knob 66, current will flow in either one direction or theother through coil 52, accordin to the position of sliding contact 56,WlllCll will be indicated on the scale 58.-

Current from potentiometer 55 flows throu h conductor 67 to one end ofcoil 51 and tl1us,'by connection 68 which is common to both coils 51 and52, back tothe middle point of the battery 53. Conseuently current mayflow in either direction mm the coil 51 according to the indication ofthe sliding contact 57 on the. scale 59. Graduations on the scales 58and 59 are preferably made in seconds. The knob 66 may be held downafter being depressed by catch 69, which is released once in everytwelve hours by the pin 70 in the hour hand gear 71 of 'the clock.Consequentl the circuit through coil 52 which lnclud es potentiometer 54can onl be. left closed for'somewhat less than two ve hours. The effectof current passing through either of coils 51 or 52 is to accelerate orretard motion of the pendulum 10 according to the direction of thecurrent through these coils, and the amount of acceleration orretardation will depend upon the strength of the current. This isdetermined by the Potentiometers 54 and 55. If the sliding contacts 56and 7 are in their mid position there will be zero potential across theterminals of the coils and consequently no current will flow. 011deviation of the sliding contacts in one direction, the effect of thecurrent will be to make the clock run faster, and the deviation of theslidin contact in the other direction will make t e clock run slower.

The scale graduations 59 are preferably such as will correspond to theacceleration or retardation of the clock of one second in twenty-fourhours, and the scale graduations 58 correspond preferably withacceleration or retardation of one second in somewhat less than twelvehours. AS a result of this arran ement, the clock may be set by means 0potentiometer -54, by depressing the knob 66 and sliding the contactor56 so that the other end which passes over the scale will correspondwith the number of seconds which the clock should gain or lose. Thisoperation of setting must be performed -just after the pin 70 haspermitted the arm 72 to drop so that the catch 69 may become effective,and it is usually arranged so that this result will take place aboutnoon or mid-night when clocks are normally set.

The retardation or acceleration produced through potentiometer 54 willbe effective for the next twelve hours only, so that the clock will notgain nor lose after the catch 69 has been released. The potentiometer 55however, on the other hand remains in circuit constantl and consequentlyproduties a constant e ec-t through coil 51 on the pendulum 10.Therefore by means of 'mally with an error less than one operator in anelectric power station. The

synchronous motor 27 is connected to the bus bars so as to respond tothe frequency of the alternating current being generated. The spring 14is wound at the point 43 and the pendulum is started. The hands 35, 26of the clock are then set to correspond with the true time, beingexactly over each other.

The operator is instructed to adjust thefrequency so as to maintainthese hands together. He can do this very easily by observing the clockoccasionally, say at half hour intervals and knowing'whether the hand 35has a tendenc to gain or lose in respect to hand 26. f he finds that thehand 35 is gaining he will slow down the speed governors of theturbines, or speed them up if he finds that the hand 35 is losing.

Experience has demonstrated that in large power stations it is very easyto keep 'the hands together within two or three seconds. bycomparatively infrequent adjustment of the speed governors. Each day, atnoontime preferably, the readin of the hand 26 should be compared with te true time 'received by wireless ,from- Washington or otherwisedetermined, and then the rate of the clock should be corrected by meansof potentiometer 55 and the error of the clock should be corrected bypotentiometer 54. clock made in this manner, will run norsecond per day.The motor 27, which is running constantly will keep the spring '14 whichdrives the pendulum. always wound at exactly the same tension.

In Fig. 1, the standard 3 time keeper: is shown as provided with amain sring and controlled by a pendulum, but it is not desired to limit theinvention in this respect, as a duplex master clock may be provided inwhich the standard time keeper may be otherwise driven as for instanceby a synchronous motor M as shown in Figs. 4and 5. so that its rate iscontrolled by the freqliliency of the current which is supplied totemotorM. W

The master clock shown in Figs, 4 and 5. may be used in the .powerhouse'ofan isolatedplant and the alternating current for the motor M maycome from a large power station which is provided with a pen-- dulummaster clock shown in Fig. 1, and the current; so plied to the secondsynchronous motor 27 in Figs. 4 and 5 may be received from the bus barsof the isolated plant, for example, a manufacturing plant which suppliesits own power. It willthus be seen that by means of the modified masterclock shown in Figs. 4 and 5, it is easy for the engineer of theisolatedplant to maintain the same average frequency as the large powerstation without purchasing-any electrical energy from the large powerstation, excepting the insignificant amount necessary to drive the tinysynchronous motor M.

The motor M is connected through gears 80. 81, 82, 83 with the hand 26,and the motor 27 through .gears- 30, 31, 32. 33, with the hand 35. Themethod of using the clock shown in Figs. 4 and 5 is the same as has beenheretofore described. -The means for regulating the rate of the pendulumof the standard time keeper is not herein claimed as it forms thesubject-matter of a divisional application Serial Number 390,014 filedby me on June 18, 1920.

Claims: 1. In an instrument of the character de-v scribed, a standardclock, a synchronous motor, two hands mounted concentrically,

connections between one hand and the standard clock and between theother hand and the synchronous motor, so proportioned that both handsrevolve normally at the same rate, and connections between the synchronous' motor and the driving mechanism ofthe standard c'lockwherebythe spring of the latter is kept constantly wound. p 2. In aninstrumentof the character described, a clock movement provided with amain springand with a time element rotatablethereby, a second-timeelement concentric'ally mounted with relation to the first mentionedtime element, 'a synchronous motor, gearing connecting said motor withsaid second time element, and gearing connecting said synchronous motorwith the main spring of the clock .towind up the same.

3. In an instrument of the character (10- scribed, a clock movementprovided with a main spring; a time element, and gearing connectingsaid'time element with said main spring to be continuously rotatedthereby, a

;second time element concentrically mounted with relation to thefirst-mentioned time element. a synchronous motor, and gearingconnecting the second time element with the synchronous motor to becontinuously driven thereby, and soproportioned with relation to thegearing of the clock movement as to normallyrotate the second. timeelement at the same rate as the first-mentioned time element wherebyvariations in the synchronism of the-two motors are instantlyvisualized.

4. In an' instrument of the character described, a time element, a clockmovement provided with gearing connected with said time element torotate the latter, a second time element concentrically mounted withrelation to the first-mentioned time element,

a synchronous motor, and gearing connecting variations in the chronismof the clockthe second time element with the synchronous movement and oft e synchronous motor are motor to be continuously driven thereby, an

d instantly visualized. so proportioned with relation to the gearing Intestimony whereof, I have signed my of the clock movement as to normallyrotate name to this specification. the second time element at the samerate as the first-mentioned time element, whereby HENRY E. WARREN.

